apollo-smith: add arbitrary generation of ignored tokens

[bnjjj]

Be able to generate ignorate tokens in a valid document (commas, whitespaces, comments, ...)

Example:

# only customers can use it
type Cat       implements Pet @tag(name: "team-customers") {
    #cat name
    name: String,,,,


    age: Int 

    napSpot: NapSpot, , , # where the snoozing happpens
}